Aldo was one of "The Others" and was responsible for guarding a DHARMA InitiativeHydra Station compound where Karl was being held prisoner. While reading "A Brief History of Time", Alex arrived with Kate and Sawyer with the intent of ambushing Aldo for access into the compound. With Kate and Sawyer at gunpoint, Alex states that they escaped from their cages, and that her father, Ben, told her to bring them there. Aldo uses his radio to contact Pickett and informs him of the situation, while Pickett explains not to trust Alex, Aldo is tackled by Sawyer and informed that he fell for the "Wookiee Prisoner Gag". Alex asks where Karl is being held, however, Aldo refuses to give information on his whereabouts, until Kate threatens to shoot him in the knee. He reveals that Karl is being held in Room 23, and the keys are in his back pocket, upon hearing this, Kate hits Aldo with the butt of the rifle.

Pickett, Jason and Ivan arrive and Pickett forcefully wakes Aldo up demanding to know where they went. Aldo states that he doesn't know, but Alex is with them. Juliet then arrives and explains the situation to them that Ben requested they go free.

Aldo is ordered by Dogen to help Jin and Kate find Sawyer and bring him back to the Temple. Kate knocks out Aldo and his partner, Justin, then Jin leaves Kate and heads back to the temple. Jin is then caught by Aldo and Justin. Aldo was about to kill Jin when Claire saves Jin and kills Aldo and Justin.